This invention relates to automatic washing machines of the vertical axis type and more particularly to a filter system for such automatic washing machines.
Because of mechanical agitation to which articles of clothing are subjected in the conventional washing machine, and the resulting flexing and turnovers of the fabrics, a very appreciable amount of short fibers or lint is separated from the fabrics. This lint remains in suspension in the water, and during centrifugal extraction of the washing liquid following the washing of clothes, much of the lint will remain trapped or be redeposited on the articles of clothing. Even though automatic washing machines generally include subsequent rinsing operations, it has been found that much of the lint is retained in the rinsing water and, unless removed from the circulating wash water, it is again trapped in the articles of clothing during the final extraction of the water.
U.S. Pat. No. 4,357,813 discloses a truncated filter cone constructed of a rigid material such as polypropylene fastened beneath the bottom of a clothes basket. The filter cone comprises a generally truncated conical shape which is positioned adjacent the bottom wall of the basket near the upper end of the cone and is spaced from the bottom wall of the basket at the lower end of the cone. The lower end or periphery of the cone has upwardly and outwardly extending rigid teeth spaced closely subjacent the bottom wall of the basket along a generally circular line.
As a pumping agitator mounted in the basket draws liquid along a path radially inwardly from the periphery of the tub sump beneath the basket, lint carried by the liquid is trapped on and between the teeth of the filter cone. The liquid is drawn through apertures in the bottom wall of the basket and into the basket through the agitator. The liquid then flows outwardly toward the sump to repeat the cycle.
During the direct-into-spin portion of the cycle, a pressure differential is established by the spinning of the basket, tending to cause laundry liquid to flow back into the basket through the openings in the bottom wall. During this portion of the cycle, the rotating rigid filter teeth provide a pumping action to oppose this flow and along with the conical shape of the filter prevent sand or sediment from returning to the basket to be deposited on the clothing.
As the water level within the tub is decreased by the drain pump, the pumping action of the filter teeth causes water to flow outwardly from the basket through the openings in the bottom of the basket, thereby automatically cleaning the filter teeth. The lint then moves to drain from the tub along with the laundry liquid, thus automatically effecting a cleaning of the filter without manual intervention.